沁新煤礦1.8Mta新井設(shè)計(jì)含5張CAD圖-采礦工程.zip
沁新煤礦1.8Mta新井設(shè)計(jì)含5張CAD圖-采礦工程.zip,煤礦,1.8,Mta,設(shè)計(jì),CAD,采礦工程
Strategies for follow-up care and utilisation of closing and flooding in European hard coal mining areas
Abstract
The already implemented or near end of mining in the European hard coal mining areas will cause the rise of the water table which had been kept down for mining activities, and will finally re-establish the contact with the groundwater layers near the surface. This flood water causes contaminations of groundwater used for drinking water and therefore calls for immediate action, because of the in part high salinity and concentration of mobilization products from the oxidised rocks. On the other hand the long-term process offers new options for discharge optimisation and utilisation. The FLOMINET project carried out within the frame of the European RFCS programdevelops numericalmodels to forecast the impact of regional minewater rebound on mine, ground and surface water in interconnected underground hard coal mines. The research is also dedicated to the industrial utilisation of the rising mine water for renewable energy in form of electricity and geothermal heat. For this purpose numerical models have been enhanced in terms of density and temperature to become a practical planning tool for these activities. One additional application is the appraisal of gas reservoirs for methane gas extraction, the influence of the flooding process on such extraction, and the forecast of risks originating from mine gases dissolved in water after mine flooding.
1. Introduction: implications of closing and flooding in European hard coal mining areas
The development of coal consumption, worldwide exploration of coal deposits, transport conditions and world market prices have caused intensive effects on European hard coal mining areas in the last decades. Closure and flooding affected the mining areas in France, Belgium and England first but also Germany, where currently only 5 mines have remained active. The last of these mines is supposed to be closed by 2018. The flooding process in the Ruhr area becomes evident by the recent water level distribution. Even when taking the northern dip of the coal bearing strata into account, the 3 active mines appear as islands surrounded by abandoned mines with at least partial water accumulation.
Furthermore, large mining areas in Spain and even in Poland are equally affected by a closing process induced by the exploitation progress and shifting of mining activities.
In spite of site specific geological settings and varying mining technologies there are common processes accompanying the closure of mines established in Carboniferous strata in central Europe:
? The oxidation of pyrite in coal and host rock during active mining and ventilation forms a pool of soluble iron salts, which can be mobilized during flooding . Subsequent mine water drainage is mostly affected by iron concentrations demanding water treatment before discharge. The flushing of these oxidation products can take decades.
? The rising of the water table into the overlying strata may cause contact between mine water and the overlying groundwater aquifer, which was not possible under pre-mining conditions. This may affect groundwater quality and, because of subsidence, also the groundwater level requiring intensive long term pumping activities .
? Mine water flowing through deep mine voids shows high temperatures which in some cases reach more than 30 °C and might demand cooling before discharge. However, this also offers the chance for geothermal heat recovery when the mines are situated in a densely populated area and the pumping costs are not charged to the user. In addition, the geothermal potential accessed by the mine voids can be used by closed loop systems.
? The rocks caved by longwall mining are very sensitive to water and as they are constituted by an assemblage of blocks, the equilibrium found may be affected by the presence of water and a disturbance of the surface either by resettlement or uplift. Additionally, volumetric changes due to swelling of coal and clays upon water saturation contribute to uplift processes.
These demands and potentials of the mine closure process show the requirement for the coordination of this process not only taking into account the economics of a short-term decommissioning but also the ecological and, the long-term economic situation. Flooding processes and their various impacts do not take place in a linear way. Fig.1 illustrates the development of water levels in the Lorraine coal basin. Strategies for follow-up care and utilisation of mine closing and flooding require specially adopted model tools in order to provide forecasts of water table developments and environmental impacts on the surface.
Fig.1
2. The modelling tool Boxmodel
The Boxmodel program code forms an application orientated model tool for water flow, mass transport, heat transport and interaction in water–gas-systems. In most cases mining fields with intensive mining activities resulting in a homogenously reacting hydraulic system are taken as boxes in the Boxmodel. These boxes are subdivided vertically into model slices and form the balance elements for all calculations . The software allows for defining the structure of modelling cells and for installing many different kinds of connections among mining fields.
The Boxmodel already serves as a prognostic tool for mine water issues in some important hard coal mining areas. Meanwhile considerable data are available to verify input parameters and assumptions.DMT has continued the development of the Boxmodel with the objective to improve the practicability and to standardise the methodology at various sites. In addition to the improvement of the already well established mine water flow models some important innovative programme codes have been implemented to model the following processes: coupled gas-water flow, energy production, high turbulent flow (storage), coupling of mine water with near surface ground water models and heat transport .
The concept of the Boxmodel allows coupling of the mine model with groundwater aquifer models. Groundwater aquifer layers can be discretised by the Boxmodel in geometry and quality identically to the world wide most accepted groundwater models likeMODFLOW(finite difference method) or FEFLOW (finite element models). There is also the option to couple existing groundwater models.
Apart from the water balance the most relevant input data comprise the void volume which includes open drifts,workings (remaining voids after subsidence in the gob) and porosity of the rocks. The chemical composition of the water is required for the investigation of quality effects. The transport-tool of the Boxmodel is considering the transport phenomena convection, molecular diffusion, dispersion, geochemical solution-/precipitation processes, sorption / desorption as well as microbiological processes. The Boxmodel is a multimigrant reactive mass-transport model. Up to now 30 inorganic and 27 organic chemical componentsare considered.
Detailed regional Boxmodels have been developed for the mining areas of the Ruhr Area.Saar Area, Lorraine Coal Basin, Asturias, Upper Silesian Coal Basin and the Durham Coal field. A coupled interactive optimisation tool will allows cenario analysis regarding impacts on energy costs, environmental protection limits, payments and fees in regional mining network scales.
3. Geothermal heat recovery
3.1. geothermal heat recovery from mine water
Due to drainage effects the concentrated mine water outflows have anomalous yield,specific chemical composition and higher temperature in comparison with natural springs. Furthermore, this temperature remains steady throughout the year (Sanner et al., 2003), making mine water suitable for geothermal energy recovery: all three elements of a low-grade geothermal system (heat source, water and permeability) are readily available . Permeability is extensively present due to mine workings (in addition to fracture zones) while water is abundant below the water table.
3.2. Technical feasibility of geothermal recovery in Asturias Carboniferous Basin: Geothermal potential assessment
The shaft of the Barredo Colliery has been selected for detailed geothermal study due to an average water temperature between 20 °C to 25 °C. This is the lowest discharge point of the regional mining infrastructure formed by Barredo, Figaredo, San José and Santa Barbara Collieries. Thus pumping costs have been optimised. Barredo Shaft is placed in the urban centre of the municipality of Mieres, at the right bank of Caudal river. In this town, the University of Oviedo was developing two new buildings, some 200m from the shaft. Barredo Shaft is located at +220 m.a.s.l. The mine has five floors and the total depth of the shaft is 362 m. As Barredo Shaft has a direct connection with Figaredo Colliery all the water from the system could be drained by the former. The average water flow here reaches 4 Mm3/year.
For the detailed studies being carried out in order to characterize the mine for geothermal energy production and to assess the evolution of its water quality, a Boxmodel of the whole Asturian Coal Basin has been generated. This allows for consideration of the hydraulic boundary conditions.
The chemical characteristics of the water must be established in order to guarantee proper design and operational reliability. Chemical analyses of Asturian mine water proved there were no corrosion problemswith the equipment. The minewaterwasmainly bicarbonate sodium water with pH above 7. However, the main water problem identified was its high hardness, exceeding in some cases 1000 mg/L. This follows that the main expected risk would be carbonate deposits that may harm the energy generation equipment. Results show that there will be some scaling problems related to this. Intermediate heat exchangers are necessary, instead of guiding the mine water directly into the heat pump. To assess the energy potential of Barredo- Figaredo Unit, an average water flow of 4 Mm3 per year has been considered. Although re-injection of the water has not been considered so far there is an option to do so in the future. Therefore, the thermal potential in the cold source can be calculated as the product of the thermal gap, the water flow, the density of the water and the specific heat:
where:
- T Thermal gap, 5 °C (on conventional heat pumps)
- V Water flow per year (4 Mm3/year)
- Ce Water specific heat (4186.8 J/kg °C)
- ρ Density
These data allowed estimation of the thermal potential of the mine water as 2.65 MWth at the cold source. The thermal potential of the hot focus can be calculated as:
Where We is the energy consumed by the heat pump compressor (We≈0.66 MW). The water temperature is around 23 °C and it is intended to produce energy at 40 °C, thus a standard Coefficient of Performance (COP) can reach 5
The energy supplied to the heat pump at the compressor will be around 0.66 MW, reaching a thermal potential of the hot focus of 3.31 MW of heating-cooling power.
4. Gas mobilisation, migration and extraction
Mine gas consisting of Methane, Oxygen, N2 and CO2 is the natural attendant of coal and coal mining. Closure of hard coal mines has therefore to consider interactions between water and gas in a hydro-geological context of mines during and after flooding. The corresponding processes can be described in two different approaches at two different scales.
Interactions between water level rise and gas emissions during flooding can be described with the Boxmodel at a large scale. The concept of the Boxmodel approach considers one gas phase for describing the gas-flow and a multi-component concept for the mass transport model. A minimum of two components is considered: the concentration of methane and the sumof the rest (N2, CO2, H2S). Because of the large scale of the Boxmodel the gas dissolved in water is not considered. The flooding water table forms a sharp boundary to the mine not yet flooded, but still filled with gas. After flooding of coal seams the methane source is blocked.
4.1. Gas extraction during mine voids flooding
The source-term of gas generation depends on the real gas content (given by the residual gas content in coal (kg/m3-coal) and the mass of residual coal (t) per mine field) and the permeability from the point of gas sorption to the open drift system. In the so called passive period methane flows from the seam to the drift system without a suction pressure only on basis of the higher sorption pressure in the seam. This process is the reason for uncontrolled methane emissions from closed mines . Active gas pumping results in pressure reduction in the mine voids and enhanced desorption and migration of methane to the pumping station. A typical feature of gas production in active mines is a much higher gas production rate than under post mining conditions, caused primarily by movement of geological formations (subsidence after exploitation of the coal) and secondly by artificial measures to prevent gas flow into the drifts (gas suction from seems over special drill holes).
Active gas extraction therefore provides the possibility of postActive gas extraction therefore provides the possibility of post mining hydrocarbon use with additional reduction of uncontrolled gas release into the environment. It is limited, however, by the flooding process causing gas production to cease. On the other hand diffuse gas flux to the surface is enhanced during the flooding and affects urban hard coal mining areas in the post mining stage.
The dependency of gas pressure and flow on gas pumping activities and the development of methane concentration in the Lorraine Coal Basin are shown in Figs. 2 and 3 on the basis of measuring data (BRGM) and Boxmodel results.
Fig. 2. Calculated and measured gas flow (influenced by flooding) in the Lorraine Coal Basin, Simon shaft.
Fig. 3. Calculated and measured development of the methane fraction in the gas phase in the Lorraine Coal Basin, Simon shaft.
The following input data have been considered for calibration of the gas model tool for the regional model:
- Points of gas pumping (x,y,z)
- Pressure development versus time p(t)
- Volume of gas pumped
- Concentration development of methane at the pumping points
- Source term description: residual gas content in coal [kg/m3-coal]
- Mass of residual coal (t) per mine field.
The source-termof gas production (mainly the coal seams) is linked to the rising water table. Successive flooding of seams causes cut-off of the specific gas production in this source. As a result the total gas production rate is decreasing with rising water table.
The considered differential equation for the transport of the gas phase is:
with
θ – Porosity [?]
ρ – Density of gas phase [kg/m3]
u – Darcy-velocity of gas phase [m/s]
ρ q – Sink/source term of gas phase [kg/s/m3]
pg – Pressure of phase [kg/(s2m)]
On the basis of the mass-flow formula of the gas phase the transport of two components (1: methane, 2: anonym gas for dilution (CO2, O2, N2, …)) must be described (coupled one phase and two components flow). For this reason the formula of mass flow of the gas phase has to be extended by the concentration to:
with
c – Concentration of a component [1] or [100%]
4.2. Effect of flooding on gas emission at short time scale
In situ gasmonitoring performed in old shafts during the flooding of the La Houve Basin confirmed a first massive gas release just after the beginning of thewater level rise. This first period of gas flowis followed by a constant decrease until the end of the flooding. At this stage and during water level increase, gas is expelled by piston effect due to the void volume reduction.
However, there is a positive effect on gas emissions coming fromold mines just after flooding. After flooding of the last mine voids gas flow out of wells reached concentration levels (CO2, CH4 and O2) comparable to atmospheric gas concentrations. Therefore, the evolution of void volume during flooding is the main parameter which controls mine gas outflow.
5. Conclusion
In spite of obvious demand for further enhancements the model approaches seem promising for integration of post mining demands into recent strategies for mining management and closedown. In contrast to newmining projects the consequences of the mining period for the environment in the long term have not been subject to initial planning, and the recent mining structure is often the result of a long and changeful history. Appropriate model tools are available to assess the complex site data in order to develop the long termconcepts important for the overall cost effectiveness now, when mining is still active and required infrastructural procedures can be implemented.
歐洲煤炭開采區(qū)域關(guān)閉和水浸后后續(xù)關(guān)注和利用的策略
摘要
在歐洲煤炭開采區(qū)域已經(jīng)實(shí)施或者接近完成的采礦活動將會導(dǎo)致地下水位的上升，并且，將會最終導(dǎo)致重新與接近地面的地下水層建立聯(lián)系。礦井涌水導(dǎo)致用于飲用的地下水污染，因此要求立刻采取行動，原因是極易氧化的巖石具有高礦化度及大量活化產(chǎn)物的聚集。另一方面長期的過程為排放和利用提供了新的選擇。在歐洲RFCS項(xiàng)目框架內(nèi)的FLOMINEF工程開發(fā)了關(guān)聯(lián)的數(shù)值模型來預(yù)測區(qū)域礦井水在關(guān)聯(lián)煤礦地下開采區(qū)域?qū)τ诿旱V、地表以及地下水的影響。研究也致力于對于上升礦井水的工業(yè)利用，以電力和地?zé)岬男问将@取可再生能源?；谶@個(gè)目的，密度以及溫度的數(shù)值模型已經(jīng)被加強(qiáng)建立來打造一種實(shí)際可行的工具，附加的應(yīng)用是瓦斯氣體提取研究，涌水過程瓦斯提取的影響以及從自溶解在水浸礦井里水里的氣體預(yù)測危險(xiǎn)性。
1、簡介：歐洲煤炭開采領(lǐng)域關(guān)閉或水浸礦井造成的影響
消費(fèi)量、全球范圍內(nèi)煤炭礦藏的勘探運(yùn)輸條件以及世界范圍內(nèi)煤炭市價(jià)格的上漲導(dǎo)致在過去的十年里對歐洲煤炭開采活動造成巨大影響。礦井封閉以及涌水影響著法國比利時(shí)英國以及德國，在那里只有五座礦山仍在生產(chǎn)。這下煤礦將會在2018年相繼關(guān)閉，通過最近的水位分不可見魯爾區(qū)的礦井水淹過程非常明顯，甚至將北部含煤地層的傾角考慮在內(nèi)，三條生產(chǎn)礦山呈現(xiàn)為被局部積水廢棄礦山的島嶼。此外，在西班牙和波蘭大的煤礦開采區(qū)域被關(guān)閉礦井以及采礦活動轉(zhuǎn)移影響著，盡管有特殊的礦床地質(zhì)特征和不同的采礦技術(shù)，在歐洲中部伴隨著礦山關(guān)閉有著類似的過程：
（1）在采礦和通風(fēng)期間黃鐵礦在煤層和圍巖中的氧化形成了可溶性鐵鹽池可以在水浸過程中移動。隨后的礦井排水被鐵濃度影響，沖流這下氧化物需要十年以上的時(shí)間。
（2）上升的地下水位引起礦井水和上覆地下水含水層的聯(lián)系，這是在不開采煤礦的條件下不可能發(fā)生的，可能影響地下水質(zhì)量，因?yàn)橄孪莸牡叵滤恍枰芗拈L期的抽水活動。流經(jīng)深礦孔隙的礦井水顯示出高溫在，在某種程度上可以超過30攝氏度，因此也需要在排放抽取前冷卻處理，但是，這同樣提供了地?zé)峄厥盏臋C(jī)會。當(dāng)?shù)V井坐落在人口稠密區(qū)以及抽水費(fèi)用可以不用向用戶收取。另外，礦孔隙產(chǎn)生的地?zé)釢摿梢员粦?yīng)用于閉環(huán)系統(tǒng)。
（3）長壁開采塌陷的巖石對水很敏感，由于他們是塊體集合組成，平衡可能因?yàn)樗拇嬖诙蓴_。另外，由于煤和粘土體積膨脹變化有助于提升流程。
這些要求和礦山關(guān)閉過程的潛在問題，表明協(xié)調(diào)這個(gè)過程的要求不僅要考慮到短期的退役經(jīng)濟(jì)效益也要考慮生態(tài)的經(jīng)濟(jì)形勢。水淹過程及各種影響不采取線性方式進(jìn)行。圖二說明了洛林煤盆地地下水位的發(fā)展?fàn)顩r。對于礦山關(guān)閉及涌水后期的后續(xù)關(guān)注和利用的策略需要專門的模型工具，目的是為了提供礦井水位和地表環(huán)境影響準(zhǔn)確的預(yù)報(bào)。
2、建模工具BOXMODEL
BOXMODEL程序代碼里包含水流、運(yùn)輸、熱運(yùn)輸以及水汽系統(tǒng)的相互利用。在大多數(shù)的情況下，伴隨著強(qiáng)烈采礦活動的井田在BOXMODEL中被當(dāng)做一個(gè)箱子垂直細(xì)分成模型切片以及形成用于所有計(jì)算的平衡元素。該軟件允許定義建模細(xì)胞的結(jié)構(gòu)和架構(gòu)許多不同采礦領(lǐng)域之間的連接。BOXMODEL模型已經(jīng)作為一個(gè)預(yù)測工具在一些重要的煤礦開采領(lǐng)域。同時(shí)，大量的數(shù)據(jù)可用來驗(yàn)證輸入?yún)?shù)和假設(shè)。DMT促進(jìn)了BOXMODEL的發(fā)展，提高了模型的實(shí)用性以及在不同領(lǐng)域的規(guī)范方法。除了已經(jīng)建立的礦井水量流動模型的改善，一些重要的創(chuàng)新程序代碼已經(jīng)被實(shí)施模擬一下過程：耦合氣水流量、能量產(chǎn)生高湍流、礦井水以及附近的地表水模型的耦合及熱傳輸。
BOXMODEL的理念要求礦井模型與地下含水層模型的耦合，地下含水層可以被BOXMODEL在幾何形狀和質(zhì)量離散成。世界范圍內(nèi)都可以接受的像BOXMODEL或FEFLOW地下水模型。也有選擇去耦合已有的地下水模型。
除了水平衡，最大相關(guān)的輸入數(shù)據(jù)包括孔隙體積，里面包括開放的飄移運(yùn)作以及巖石的孔隙密度。水的化學(xué)成分需要質(zhì)量影響的調(diào)查。交通的BOXMODEL正在考慮運(yùn)輸對象對流、分子擴(kuò)散、分散、地球化學(xué)解決方案、降水過程、吸附、脫附及微生物過程。BOXMODEL是一個(gè)反應(yīng)性運(yùn)輸集體模型，到現(xiàn)在為止，30個(gè)無機(jī)27個(gè)有機(jī)的化學(xué)成分被考慮。
魯爾區(qū)、節(jié)爾區(qū)、洛林煤盆地、阿斯圖里亞斯、上西里西亞煤盆地和達(dá)勒姆盆地已經(jīng)制定了詳細(xì)的區(qū)域BOXMODEL模型。耦合互動的優(yōu)化工具將允許分析有關(guān)能源成本的影響、環(huán)境保護(hù)限制以及在區(qū)域采礦網(wǎng)絡(luò)規(guī)模的支出和費(fèi)用。
3、地?zé)峄厥?
3.1、礦井水里地?zé)峄厥?
由于排水效果，集中礦井水流出和天然泉水比較有異常收益率、特殊化學(xué)成分和較高的溫度。而且，溫度全年保持穩(wěn)定，使得礦井水適合地?zé)峄厥?。低檔的地?zé)嵯到y(tǒng)的所有三個(gè)要素隨時(shí)可用。由于采礦活動，滲透率普遍存在而且在地下水位一下水量是豐富的。
3.2、阿里斯圖里盆地地?zé)峄謴?fù)技術(shù)的可行性：地?zé)釢撃茉u估
由于平均水溫在20-25℃，巴雷煤礦軸已經(jīng)被選定為詳細(xì)的地?zé)嵫芯浚砂屠追羌永锥?、圣巴巴拉煤礦形成的，這是該區(qū)域的采礦基礎(chǔ)設(shè)施的最低排放點(diǎn)。因此，抽水成本卻得到了優(yōu)化，巴雷軸位置在mieres直轄市的城市中心，在尾鰭河右岸。在這個(gè)城鎮(zhèn)，奧維多大學(xué)正在開發(fā)兩個(gè)新的建筑，離軸大概200米，巴雷軸位于+220米a.s.l。礦井有五層和軸的總深度為362米，由于巴雷軸有一個(gè)直接與煤礦菲加雷多連接所有的水能由前一個(gè)倒掉，這里的平均水流量達(dá)到4m3/a。
對于正在開展的詳細(xì)研究，為了描述為熱能生產(chǎn)的礦井且評估水質(zhì)的深度，整個(gè)阿里圖里亞斯盆地BOXMODEL已經(jīng)產(chǎn)生，這需要考慮壓力邊界條件。
為了保證適當(dāng)?shù)脑O(shè)計(jì)和運(yùn)行的可靠性，水的化學(xué)特性數(shù)據(jù)庫必須建立。阿斯圖里亞斯礦井水的化學(xué)特性分析證明設(shè)備無腐蝕問題。礦井水主要是碳酸氫鈉，水的PH值超過7.然而，確定的主要水問題是其硬度高，某些情況下超過1000毫升/升,這帶來的主要問題是碳酸氫鹽的沉積，可能會損害能源發(fā)電設(shè)備，結(jié)果顯示將產(chǎn)生與之關(guān)聯(lián)的一些縮放問題，中間熱交換器是必要的，而不是指導(dǎo)礦井水直接進(jìn)入熱泵,要評估的巴雷-菲加雷多單位的能源潛力，每年平均水流量4萬立方米已被考慮。雖然到目前為止還沒有考慮重新注入水，在未來可能這么做。因此，在冷源內(nèi)，產(chǎn)品的熱差距，水流，水的密度和比熱，熱的潛力就能被計(jì)算。
其中：
- T的熱差距，5℃（常規(guī)熱泵）
- V的每年水流量（4 Mm3/year）
- 鈰水的比熱（4186.8焦耳/公斤°C間）
- ρ密度
這些數(shù)據(jù)使礦井水作為冷源的2.65 MWth熱潛力的估計(jì)。熱潛力可熱議的焦點(diǎn)計(jì)算公式為：
這里We是由熱泵消耗的能量壓縮機(jī)（≈0.66兆瓦）。水溫約23°C和標(biāo)準(zhǔn)的性能系數(shù)（COP）的目的是在40°C產(chǎn)生的能量，從而可以達(dá)到5
壓縮機(jī)的熱泵提供的能量將達(dá)到約0.66萬千瓦，達(dá)到了熱勢熱議的焦點(diǎn)
加熱制冷功率3.31兆瓦。
4、氣體的流動，遷移和提取
甲烷，氧氣，氮?dú)夂投趸冀M成的煤礦瓦斯伴隨著煤炭和煤炭開采，Alpha煤礦的關(guān)閉，因此要考慮洪水期間和之后的礦山水文地質(zhì)環(huán)境的水和氣體之間的相互作用, 相應(yīng)的進(jìn)程可以用兩個(gè)不同的尺度兩種不同的方法描述。
在水浸過程中水位上升和氣體排放量之間的相互作用可以大規(guī)模利用BOXMODEL來描述，BOXMODEL方法的概念吧一個(gè)流形氣態(tài)描述為集體運(yùn)輸模式和多組分的概念。被認(rèn)為最低的兩個(gè)組成部分：甲烷濃度和其余的總和的濃度（氫氣、二氧化碳、硫化氫）。因?yàn)锽OXMODEL是大規(guī)模的模型，溶解在水中的氣體不予考慮。水位形
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